How to use a mortgage calculator to save thousands

A mortgage calculator is one of the simplest yet most powerful tools for anyone buying a home or managing an existing mortgage.

What a mortgage calculator shows

It shows monthly payment, interest vs principal split and an amortization schedule. It does not always include taxes, insurance or closing costs — add those separately for a full picture.

Compare terms

Run 15- and 30-year scenarios and compare monthly payments and total interest. Shorter terms save interest but raise payments.

Test extra payments

Enter an extra monthly amount or a one-off lump sum to see how much time and interest you save.

Use it for refinancing

Compare your current loan to a hypothetical refinance and compute break-even months (closing costs ÷ monthly savings).